Various methods of embedding a watermark in an information (e.g. video, audio) signal, and corresponding methods of detecting said watermark, are known in the art.
International patent application WO99/12331 discloses a known embedding and detecting method. In this prior art method, different watermark patterns are embedded in respective sections of an information signal (here: image blocks into which the image is divided). Such a watermark, which is built up from a finite number of basic pattern by tiling, is herein referred to as a pseudo-symmetric watermark.